/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package com.sun.org.apache.bcel.internal.generic;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import com.sun.org.apache.bcel.internal.Constants;
import com.sun.org.apache.bcel.internal.classfile.*;
import java.util.ArrayList;
import java.util.Iterator;

/**
 * Template class for building up a field.  The only extraordinary thing
 * one can do is to add a constant value attribute to a field (which must of
 * course be compatible with to the declared type).
 *
 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 * @see Field
 */
public class FieldGen extends FieldGenOrMethodGen {
    private Object value = null;

    /**
     * Declare a field. If it is static (isStatic() == true) and has a
     * basic type like int or String it may have an initial value
     * associated with it as defined by setInitValue().
     *
     * @param access_flags access qualifiers
     * @param type  field type
     * @param name field name
     * @param cp constant pool
     */
    public FieldGen(int access_flags, Type type, String name, ConstantPoolGen cp) {
        setAccessFlags(access_flags);
        setType(type);
        setName(name);
        setConstantPool(cp);
    }

    /**
     * Instantiate from existing field.
     *
     * @param field Field object
     * @param cp constant pool (must contain the same entries as the field's constant pool)
     */
    public FieldGen(Field field, ConstantPoolGen cp) {
        this(field.getAccessFlags(), Type.getType(field.getSignature()), field.getName(), cp);

        Attribute[] attrs = field.getAttributes();

        for (int i = 0; i < attrs.length; i++) {
            if (attrs[i] instanceof ConstantValue)
                setValue(((ConstantValue) attrs[i]).getConstantValueIndex());
            else
                addAttribute(attrs[i]);
        }
    }

    private void setValue(int index) {
        ConstantPool cp = this.cp.getConstantPool();
        Constant c = cp.getConstant(index);
        value = ((ConstantObject) c).getConstantValue(cp);
    }

    /**
     * Set (optional) initial value of field, otherwise it will be set to null/0/false
     * by the JVM automatically.
     */
    public void setInitValue(String str) {
        checkType(new ObjectType("java.lang.String"));

        if (str != null)
            value = str;
    }

    public void setInitValue(long l) {
        checkType(Type.LONG);

        if (l != 0L)
            value = new Long(l);
    }

    public void setInitValue(int i) {
        checkType(Type.INT);

        if (i != 0)
            value = new Integer(i);
    }

    public void setInitValue(short s) {
        checkType(Type.SHORT);

        if (s != 0)
            value = new Integer(s);
    }

    public void setInitValue(char c) {
        checkType(Type.CHAR);

        if (c != 0)
            value = new Integer(c);
    }

    public void setInitValue(byte b) {
        checkType(Type.BYTE);

        if (b != 0)
            value = new Integer(b);
    }

    public void setInitValue(boolean b) {
        checkType(Type.BOOLEAN);

        if (b)
            value = new Integer(1);
    }

    public void setInitValue(float f) {
        checkType(Type.FLOAT);

        if (f != 0.0)
            value = new Float(f);
    }

    public void setInitValue(double d) {
        checkType(Type.DOUBLE);

        if (d != 0.0)
            value = new Double(d);
    }

    /** Remove any initial value.
     */
    public void cancelInitValue() {
        value = null;
    }

    private void checkType(Type atype) {
        if (type == null)
            throw new ClassGenException("You haven't defined the type of the field yet");

        if (!isFinal())
            throw new ClassGenException("Only final fields may have an initial value!");

        if (!type.equals(atype))
            throw new ClassGenException("Types are not compatible: " + type + " vs. " + atype);
    }

    /**
     * Get field object after having set up all necessary values.
     */
    public Field getField() {
        String signature = getSignature();
        int name_index = cp.addUtf8(name);
        int signature_index = cp.addUtf8(signature);

        if (value != null) {
            checkType(type);
            int index = addConstant();
            addAttribute(new ConstantValue(cp.addUtf8("ConstantValue"), 2, index, cp.getConstantPool()));
        }

        return new Field(access_flags, name_index, signature_index, getAttributes(), cp.getConstantPool());
    }

    private int addConstant() {
        switch (type.getType()) {
            case Constants.T_INT:
            case Constants.T_CHAR:
            case Constants.T_BYTE:
            case Constants.T_BOOLEAN:
            case Constants.T_SHORT:
                return cp.addInteger(((Integer) value).intValue());

            case Constants.T_FLOAT:
                return cp.addFloat(((Float) value).floatValue());

            case Constants.T_DOUBLE:
                return cp.addDouble(((Double) value).doubleValue());

            case Constants.T_LONG:
                return cp.addLong(((Long) value).longValue());

            case Constants.T_REFERENCE:
                return cp.addString(((String) value));

            default:
                throw new RuntimeException("Oops: Unhandled : " + type.getType());
        }
    }

    public String getSignature() {
        return type.getSignature();
    }

    private ArrayList observers;

    /** Add observer for this object.
     */
    public void addObserver(FieldObserver o) {
        if (observers == null)
            observers = new ArrayList();

        observers.add(o);
    }

    /** Remove observer for this object.
     */
    public void removeObserver(FieldObserver o) {
        if (observers != null)
            observers.remove(o);
    }

    /** Call notify() method on all observers. This method is not called
     * automatically whenever the state has changed, but has to be
     * called by the user after he has finished editing the object.
     */
    public void update() {
        if (observers != null)
            for (Iterator e = observers.iterator(); e.hasNext();)
                ((FieldObserver) e.next()).notify(this);
    }

    public String getInitValue() {
        if (value != null) {
            return value.toString();
        } else
            return null;
    }

    /**
     * Return string representation close to declaration format,
     * `public static final short MAX = 100', e.g..
     *
     * @return String representation of field
     */
    public final String toString() {
        String name, signature, access; // Short cuts to constant pool

        access = Utility.accessToString(access_flags);
        access = access.equals("") ? "" : (access + " ");
        signature = type.toString();
        name = getName();

        StringBuffer buf = new StringBuffer(access + signature + " " + name);
        String value = getInitValue();

        if (value != null)
            buf.append(" = " + value);

        return buf.toString();
    }

    /** @return deep copy of this field
     */
    public FieldGen copy(ConstantPoolGen cp) {
        FieldGen fg = (FieldGen) clone();

        fg.setConstantPool(cp);
        return fg;
    }
}
